Buffer guarded rope and method for forming the same



Sept. 19, 1961 F. H. SWANSER 3,000,171

BUFFER GUARDED ROPE AND METHOD FOR FORMING THE SAME Filed Nov. 18, 1957 4 Sheets-Sheet 1 INVENTOR) FRANK H. SwA NSERJ- TTORNEY Sept. 19, 1961 F. H. SWANSER BUFFER GUARDED ROPE AND METHOD FOR FORMING THE SAME Filed Nov. 18, 1957 4 Sheets-Sheet 2 INVENTOR. FRANK JWANSER ATTORNEY 2 an 33 3 3 3: 3 2 J1 M 3 /v '5 11 2/) I I I 4 Sheets-Sheet 3 INVENTOR. FRANK H. SWANSER ATTORNEY Se t. 19, 1961 F. H. SWANSER BUFFER GUARDED ROPE AND METHOD FOR FORMING THE SAME Filed Nov. 18, 1957 Sept. 19, 1961 F. H. SWANSER BUFFER GUARDED ROPE AND METHOD FOR FORMING THE SAME Filed Nov. 18, 1957 4 Sheets-Sheet 4 INVENTOR. EMA/K H. SWA/VsER ATTORNEY United States Patent G 3,000,171 BUFFER GUARDED ROPE AND METHOD FOR FORMING THE SAME Frank H. Swanser, Gardena, Califl, assignor to Swarn Company, Gardena, Calif, a co-partnership Filed Nov. 18, 1957, Ser. No. 697,043 8 Claims. (Cl. 57-153) The present invention relates to buffer guarded rope and the means for fabricating the same.

By buffer guarded rope, I mean a rope, the strands of which are treated so as to be wear resistant, in that it resists abrasion, fraying and stranding. Ropes vary as to the material used in their fabrication, such as wire ropes, synthetic fiber ropes, cotton ropes, hemp, and other materials. Ropes, whether of synthetic fiber or natural fiber, are usually formed from individual strands and, as a rule, these strands are wound together on a helix, the pitch of which may vary. The outer exposed surface of the rope formed by the strands is the portion which is subjected to wear, and the present invention is directed to a bufier means applied to the strands for the purpose of absorbing wear and resisting abrasive action which would normally be taken by the strands per se of the rope.

An object of the invention is to provide a bufier guarded rope, the bufier of which acts to increase the wear life of the rope.

A further object is the provision of a buffer guarded rope wherein synthetic fiber rope may be utilized, and the synthetic fibers protected from direct abuse.

A further object is to provide a buffer guarded rope which will Withstand stretching, bending, twisting and kinking without damage to the buffer area, and which is resistant to compression and tension, and localized stresses.

A further object is to provide a buffer for ropes which is capable of withstanding temperature extremes and likewise withstanding the deleterious eifects of sea water, acids, greases, oils, and the effects of sunlight and weather.

A further object is the provision of a buflFer for the periphery of a rope which may be vulcanized or otherwise made to cohere permanently with the multiple strands of the rope.

A further object is to provide a butter for rope that prevents unravelling and fraying of the outer strands.

It has been found that synthetic ropes are stronger than fiber ropes, with more ability to withstand stretch, shock, and resistance to rot and mildew. However, synthetic ropes are weak in that the fibers thereof offer less individual resistance to attack by abrasion. The present invention, by providing a peripheral buffer for synthetic ropes, will overcome the objection thereto above noted by giving a longer life to a rope by freeing it from the effects of abrasion.

Another object is the provision of a buffer material for ropes, and particularly natural fiber type and synthetic fiber type ropes, wherein the buffer material will have the same physical characteristics as the rope, in that the buffer material will withstand stretching, bending, twisting, and kinking without separating from the rope, as well as resisting the action of deleterious materials.

A further object is to provide a buffered rope, the buffering material for said strands of rope being capable of application to existing rope by any one of several means and methods, and wherein the bufiering material is directly impregnated and/or vulcanized into the fibers of the rope.

In the drawings:

FIGURE 1 is a fragmentary plan view of a stranded rope, the periphery of which has been treated with bufier material.

Patented Sept. 19, 1961 'ice 2 FIGURE 2 is a sectional view on the line 2-2 of FIG- URE 1,

FIGURE 3 is a sectional view on the line 3-3 of FIG- URE 1,

FIGURE 4 is a fragmentary longitudinal view, partly in section, of apparatus which may be utilized in the application of bufier material to the periphery of the stranded rope,

FIGURE 5 is a side elevation of apparatus which may be utilized for the application of a buffer material in tape form to the strands of the rope,

FIGURE 6 is a fragmentary, enlarged detail in longitudinal section, showing apparatus for applying buffer material in tape form to the strands of the rope during movement of the rope through said apparatus,

FIGURE 7 is a schematic sectional view, on a reduced scale, taken on the line 77 of FIGURE 6, and,

FIGURE 8 is a fragmentary longitudinal sectional view of further means for applying bufler material to the periphery of strands of rope.

Referring now with particularity to the drawings, and specifically to FIGURES l to 3, I have shown a length of rope formed from three strands, as shown in FIG- URE 3, at 1, 2 and 3. Each strand is made up of threads and yarns of either natural or synthetic material, and these strands are then wound or braided together in the form of a helix relative to the axis of the rope. The pitch of the helix may vary, as is obvious. Assuming, however, that the strands have the helical angle illustrated, the present invention provides a buffer zone for each strand, as indicated at 4, and this buffer zone subtends an are on the outer exposed surface of each strand of substantially or an area on each strand which would normally be subjected to wear and abrasion by contact with a wear surface, Whether it be a pulley, the ground, the side of the hull of a boat, capstan or other object. Preferably, the buffer is an integral part of the rope strands and runs in band like form, as shown in FIGURE 1, continuously with the lay of the rope. As shown, the band is of crescent or segmental form, in FIGURE 3, the greatest area of impregnation being on the outermost arc of each strand, as this is the point of greatest wear for the rope strands. The thickest portion of this impregnation therefore intersects a radius of the rope passing through the center of the strand.

This bufier area for the rope strands is preferably formed from a material adapted to be resistant to compression and tension, as well as localized stresses, to resist wear and abrasion, and yet, at the same time, be tough and pliable, with the ability to stretch, bend, twist, and kink without any ill effects as the rope strands are subjected to the conditions named. The buffer material must be capable of being vulcanized or otherwise made to cohere permanently to the multiple fibers of each strand throughout the zone of impregnation.

The buffer material is preferably formed from a rub ber composition such as, for instance, a silicone rubber stock. Such a silicone rubber stock should be characterized in that it should have tear strength and physical properties which give it high strength and high resistance to compression set, together with resistance to certain chemicals and oils, to water and to steam, with low water absorption and excellent weather resistance. Furthermore, such a material should be capable of being vulcanized and easy to handle, as well as being suitable for molding, extruding, laminating, and calendering. I have in mind a silicone rubber known as Silastic and manufactured by Dow-Corning Corporation. This material is satisfactory for the present invention as is any other material which has the characteristics which I have previously set forth.

As a summary of the general purposes of my invention, as illustrated in FIGURES l to 3, it will be observed that the buffer zone is substantially segmental with the convex surface of the buffer 4 corresponding to the general curvature or radius of the strands of the rope. While the buffer may extend eccentrically from the surface of the strands of rope, I preferably cause the buffer area to generally conform to the strand curvature and this is, of course, accomplished by methods and means as hereinafter described and shown in the remaining figures of the drawings. Primarily, my invention is characterized in the provision of a buffer which subtends an arc of the strands of the rope sufiicient to save the strands of rope from abrasion which would otherwise occur if the said 'strands were forcibly brought into contact with various objects tending to 'break the strands and, secondarily, a buffer which has characteristics adapted to resist abrasion and fraying to an extent far greater than the capabilities of the rope strands, and further, I provide a buffer for the strands of rope characterized in that the said buffer may expand and contract as the rope expands and contracts due to heat, tension, compression, and other forces, without .in any manner having the buffer separate from the fibers of the rope and without damage to the buffer.

1 refer now to one form of means which I may employ in the practice of my invention, and specifically to FIGURE 4. In this figure, I have shown the rope at 10,

V which is to be impregnated with a buffer material of some character. As is general practice, the rope is wound upon a drum or reel, not shown, and from said reel or drum, j the rope passes over the inclined face of a feeder table 11 and under a heating means, such as the infra-red lamps :shown at 12. The lamps are for the purpose of preheating the rope during its travel. A feed roller 13 at V the end of the inclined feeder table directs the rope onto a perforated plate or platform 14 held elevated relative to the base 11 of an elongated pan or tray 16, which pan or tray is adjustable as to height and leveling by the means shown at 17 and 18. This pan or tray is adapted to hold bufier material, indicated at 19, which is maintained in liquid condition by means of heat generated by any type of heat apparatus such as, for instance, the electrical heating coils 26 shown beneath the base of said tray, and which heating coils are connected in the usual manner to a source of electricity. As shown in the figure, the buffer material in liquid form is maintained at a level within the tray so that the said liquid passes through the perforations of platform or plate 14,- the platform being lower than rim height of the said tray. In the usual manner, I provide a valve control at 21 which connects through a pipe 22with a source of supply of the liquid buffer material, the valve being connected to the interior of the tray by piping 23, with a float and its arm, as shown at 24, for opening or closing the valve for the admission of buffer material into the tray to maintain the level of said material in said tray. As shown, the rope to be impregnated with the buffer material is adapted to be rotated during travel of the rope so that the surface of the rope is coated and likewise impregnated to a selected depth with said material, as hereinafter set forth. After such impregnation during travel of the rope, the rope is lifted upwardly, as shown at 25, and over and around a pair of rollers or pulleys 26 and 27, which pulleys are n1ounted upon a suitable stand 28 for rotation. The height of the pulley 26 above the foundation indicated for all of the apparatus at 29 determines the angularity of the portion 25 of the rope relative to the horizontal position therefor when contacting the platform 14. I have found it expedient to provide drying lamps, one of which is shown at 30, and which may be of the infra-red variety, prior to the buffer treated rope entering and passing through a curing oven which is shown in section at 31. -The curing oven is electrically heated, in the present showing, by means 32 and 33, between which means the rope passes. This curing oven is suitably supported by -platform 34. After passing through the curing oven, the

buffer treated rope is then moved over the rollers or pulleys 26 and 27 and is then wound upon a receiving reel or drum 35. The reel 35 is provided with an axial shaft mounted between a pair of cantilever X-frames, one of the frame members being shown at 36, with said X-frames secured to a plate'37, which plate is mounted axially on a shaft 38. The plate 37 rotates in a vertical plane and the shaft 38 in turn is passed through a pillow block structure 39, the outer end of said shaft carrying a pulley 40. Sprockets 41 and 42 are mounted on one end of the shaft which is passed through the reel 35 and the inner face of the plate 37 is formed to support an electric motor 43, the shaft of which carries a sprocket 44, there being a continuous chain 45 passed between the sprockets 41 and 44. For the; purpose of rotating the reel 35 to wind the buffer treated rope thereon, I provide what I term a level winder 46 carried by the framing 36 forward of the reel 35, and which level winder is controlled as to its leveling action by means of a sprocket 47, there being a continuous chain 48 passed between sprockets 42 and 47 for this purpose. As level winders are common in the art, no specific details are given.

To feed electric current to the motor 43, I provide a pair of slip rings at 49, which are carried on the shaft portion 50, and to rotate plate 37 and its associated cantilever X-frame supported members, I provide an electric motor at 51 carrying on its shaft a pulley 52, and between the pulleys 40 and 52 are passed one or more continuous belts 53. The feed reel may have a construction similar to that of the receiving reel 35 so far as rotation thereof is concerned, and in fact the structure just detailed for the elements 36 to 53 may be thesame. Thus, as both the feed and the receiving reels are rotated axially, they are rotated diametrically in order that the rope during its treatment with the buffer material, shall be rotated radially to its longitudinal axis.

One important feature of the present form of means for applying the buffer material is that the depth of the buffer liquid 19 may be regulated whereby only that POT, tion of the rope where rubbing and abrasion usually occurs is exposed to impregnation by the buffer material.

The perforations in the platform 14 may be chamfered to present a smooth edge to the portions of the rope in contact therewith, and also to aid in causing an undulating and massaging action as the rope is advanced over the platform surface. The liquid 19 is, as has been stated in the description of FIGURES l to 3, preferably a silicone rubber, although I do not wish to confine myself to the use of this particular material alone, as it is evident, within the teaching of my invention, that organic polysulfides, neoprene, butyl rubber, as well as other rubber derivatives and even latex, may be utilized, provided said materials have the characteristics of. wear and abrasion resistance, may be vulcanized, and will combine with the fibers of the rope, as set forth hereinbefore in this specification.

Referring now to FIGURES 5, 6 and 7, I have detailed apparatus of the type which provides for the application of a buffer ribbon or tape to the strands of the rope. In this instance, the rope is not axially rotated during travel thereof, as is the case for the apparatus shown in FIGURE 4. In FIGURE 5, a suitably supported feed or supply reel is shown at 60 with a power driven receiving feel for said rope at 61. Rope from the supply reel is passed upwardly between a pair of guide rollers 62 and 63, suitably mounted upon a frame supported platform 64, which platform likewise supports a preheating oven 65, not detailed, but similar to the oven shown at 31 in FIGURE 4; then the rope passes through oven 65 and through a buffer applicator means, designated generally as 66. After the passage aforesaid, the rope is directed through a curing oven 67 similar to the oven 65, thence between a pair of guide rollers 68 and 69 to the power driven receiving reel 61. The buffer applicator means includes a base 70 secured to the flooring 71, which likewise supports the supply and receiving-reels, various platforms such as 64 and associated members. Base 70 is provided with two parallel elevated tubular rails or trackways, one of which is shown at 72, and mounted on said trackways for movement are guide blocks 73, the :guide blocks being secured to a base 74. These guide blocks may take various forms, but in the present instance, the blocks are slotted so as to receive the guide rails 72 (see FIGURE 8, at 129 and 130).

. Mounted upon the base 74 are a pair of pedestals or standards 75 and 76 carrying axially aligned bearing blocks 77 and 78. A cylindrical drum 79 (see FIGURE .6) has annular end walls 80 and 81 provided with axially aligned arbors or mandrels 82 and 83. Said mandrels are carried within the bearing blocks 77 and 78 and, as shown, the rope is axially passed through said arbors or mandrels and through the drum 79. The arbor 82 has keyed thereto a belt pulley 84 and base 74 supports a :motor 85, the shaft of which carries a belt pulley 86, ithere being one or more continuous belts, as shown at 86, passed between said pulleys. A series of spaced helical slots, designated generally as 87, are provided in :the, drum. The pitch of the slots follows the pitch of the rope strands. Within the said drum are aligned pairs of :pressure rollers which also act to guide movement of the rope in its travel through the said drum; Thus, referring .to FIGURE 6, I provide a pair of opposed pressure and guide rollers 88 and 89, which are pitched relative to .-the axisof the drum at the pitch of the rope strands. E'Ihe mounting for each roller 88 and 89 is the same and, .therefore, one mounting will be described. Roller 89 is mounted for rotation in bolster 90, which bolster is gentrallybored at 91' and provided with at cylindrical surface at 92, for keyed slide movement within bore 93 ;-f ormed infitting 94. This fitting is an integral part of the drum. The fitting is screw-threaded at 95 to receive screw 96, the inner end of which screw is received in bore 91 and bears against a coil spring 97 positioned gwithin' said bore, whereby, by screw adjustment, the spring may be compressed to force the bolster.90 out- -wardly so that the roller 89 mayengage the rope strand with varying degrees of pressure.

As previously stated, the butter material is in tape or ribbon form and is adapted to be wound upon a reel. The slots 87 are of sufficient length to permit a reel tobe inserted within the drum and secured to said drum. In

FIGURE 6, the drum is provided internally with a supporting bracket 100 so formed that a portion thereof, 101, ,extends beyond the periphery of the drum at one end of ,a slot 87 and said portion 101 is provided with a removable pin or axle 102 for securing the bufier supply reel 103 Within the said drum, the bracket 101 mount for rotation, a roller 104 adapted for engagement with the strands'of the rope, as shown. Roller 104 is a counterroller to roller 105, which roller 105 is of the electrically heated ty pe electrical current being supplied to the heating elements by meansof slip rings, or other means, shown at 106, from a source of electrical supply. Roller 105 and its mounting is identical with the mounting described for roller 89, and hence the mounting will not be detailed. 7

It is intended that the rope, to which buffer tape or ribbon is to beapplied, should translationally move ith'rbugh .the drum. 79. at a certain speed and during said movement, that the drum 79 should be rotated so as to screw its way in a direction opposite to the direction of movement of the rope. Hence, the reason for mounting the base 74 on the rails 72 by blocks 73. In other words, movement of the assembly is permitted. However, if the speed of translational movement of the rope from feed reel to receiving reel is related to the speed of rotation of drum 79 and the application of the buffer ribbon or tape to the rope strands, no actual movement axially of the drum will occur. However, the movement allowed the drum by reason of the mounting on the rails allows the machine to compensate for slight changes in the traits lational speed of movement of the rope as well as for slight changes in rope tension which would change the pitch of the rope strands. Furthermore, as the diameter of the rope may vary during its travel, such compensation as just described permits the machine to work'at peak efliciency.

In FIGURE 6, a single applicator reel is detailed. However, it is evident that there will be as many applicator rolls and heated pressure rollers as there are strands of rope to which buffer ribbon or tape is' to be applied and, in the instance shown, there would be three tape or ribbon supply reels. If it is deemed desirable to apply several thicknesses or layers of the bufier tape or ribbon, then additional tape or ribbon supply reels would be provided, with accompanying and oppositely positioned heated pressure rollers. In actual practice, I have found it expedient to provide some friction or drag device for the butter tape or ribbon supply reel so that the tape or ribbon is held in tension as it is being transferred to a rope strand during rotation of the drum 79. The counter rollers 104 are easily replaceable so as to vary the diameter thereof in accordance with the diameter of the rope being processed. The counter rollers are free-turning and act to counter the pressure of heated roller against the rope strands. It is quite evident that the heated rollers, such as 105, act to blend and vulcanize the raw buffer tape or ribbon into the rope strand, and a number of sets thereof, together with the counter rollers employed, will be determined by the amount of heat and rolling required to vulcanize the tape material into the rope strands.

That form of the invention shown in FIGURE 8 follows the construction, to a considerable extent, shown in FIGURES 5, 6 and 7, in that I provide a hollow 'drum 12*5-having annular ends, such as shown for one end at 126, the opposite end being of similar construction, with "both ends provided with mandrels or arbors 127. 'I'he arbors are supported in the same manner as shown for the construction of FIGURES 5 and 6, and the machine base 128 carries blocks 129 for movement on tubular trackways 130, the trackways being supported upon a foundation. The drum 125, in the present instance, is not slotted. However, the drum is provided with aligned pairs of brackets 131, 132 which extend both inwardly and outwardly of the said drum and are of identical construction, for which reason, one bracket will be described. Bracket 132 is provided with a screw-threaded bore 133 and with a uniform bore 134 for that portion of the bracket which is within the said drum; The uniform bore receives a cylindrical portion 135 which is centrally bored at 136 to receive a coil spring'137. A screw 138 engages the thread of bore 133 and is utilized for oompressing the spring 137 so as to force member 135 outwardly from the cylindrical bore 134. A nozzle 139 coaxially extends from portion 135. Port 140 in said nozzle communicates with an offset fitting 141, which fitting, in turn, through a flexible tube 142, is in communication with an internal duct 143 in'the side and end walls and arbor of the drum. The duct communicates outwardly from the arbor with an annular groove 144 in a standard 145. This standard is mounted on the base 128, and is provided with adjustable-pairs of gland rings 146 and 147 to prevent leakage of any fluid passed through the duct 143. Said standard is provided with a duct 14S communicating with a fitting 149 and through a valved pipe 1'50 to the source of supply of liquid buffer material.

I may provide various types of fluid metering valves for controlling the flow of fluid through the nozzle. Preferably, the nozzle tip 151 is either closely adjacent or in actual contact with a rope strand so that as the heated liquid buffer material is fed under pressure through the ducts 143, 148 to the nozzle tip, there will be a pressure engagement of the said nozzle tip with the a 7 fibers of the. strand to rub the said bufier liquid into the strand during drum rotation and translational movement ?of the. ro'pe'through said drum.

As. stated, there will be as many stations for the application of bufier liquid to the. strands as there are strands, :for instance, three of said stations for the construction shown in FIGURE 8. The preliminary heating of the rope, as well as the final heating to vulcanize the bufier 'material. to said rope strands, will. be the same as previously described for the showing of FIGURES 5, 6 and 7. The operation, uses and advantages of my invention are as follows:

' 'Ihave previously set. forth. in detail the advantage of providing a buflier area on fiber type ropes, whether of natural fiber or synthetic material, and accordingly, I direct my remarks to the advantages of the several fmethods and apparatus shown in FIGURES 4 to 8, inclusive; The apparatus and. the method which I have shown and described. for. FIGURE 4, permits easy application of the. heated liquid butter material directly to the outer exposed surface oi the strands of the rope duringmove- -ment translationally of the rope accompanied. by axial :rotation thereof. The trough which holds the liquid bufiering' material may be. of. any length. desired so that either thin or thick applications of the buflfer. material to :the rope strands may be accomplished. Furthermore, the method detailed for FIGURE 4 is easily observed and .--kcpt under constant supervision by a single operator during rope treatment. Standard parts obtainable on the I market may be utilized, and so to this extent, the cost iQf the apparatus is reduced. considerably. It has been found that the penetration of the butter material into the fibers. is substantially uniform. and that the: buffer material appears. as a. ribbon on the periphery oi-the rope strands. Furthermore, it has been found that curing or vulcanizing. of the butter material to the strands is easily accomplished by proper regulation of. oven heat.

The. form of the invention shown in FIGURES S and -6 applies a preformed tape or. ribbon, formed of vul- ,canizable-material. to the periphery of the rope strands,

' and. this method, when desired, allows a multiple application of ribbons to the rope strands to any thickness desired, with each ribbon vulcanized. initially to the rope strands. and thereafter to the ribbon thereunder. Where it is not desired to apply a liquid buflering material. in

the manner shown for FIGURES 4 and 8, the method -of FIGURES 5 and 6 is advantageous as the inital preheating of. the vulcanizable material is rendered unnecessary. Perhaps the application of buffer material in tape or ribbon form is a cleaner operation than the application of liquid bufier' material so far as. maintenance is concerned, particularly whenv the liquid buffering material passed through internal ducts.

The tformotthe invention shown in' FIGURE 8 utilizes a liquid: buffering material, the same as for the form ;shown in FIGURE 4, 'withthe exception that nozzles are provided which may or may not rub against the periphery .of the rope strands,'and for directing the liquid bufiering material into the rope fibers. The main difference be- 'tween the method of FIGURE 8 and that of FIGURE 4 consists in rotation of the drum carrying the nozzles in FIGURE 8, while the rope moves translationally without radial rotation, while in FIGURE 4 the rope is rotated radially during translational movement, the liquid '8 trough remaining stationary- Both systems may be utilized however, 'with efficient results.

I claim:

1. As a new article of manufacture, a multiple strand rope and buffer means on each strand where the strand is exposed to abrasion, said bufier means being ribbons spaced from each other and each having a cross-section of generally segmental shape, the bufier means characterized in that it is resistant to compression, tension, wear and localized stresses to a greater extent than the nonbuflier'area of said strands.

2. As a new article of manufacture, a multi. strand rope formed of fibrous material, and a buffer area for each strand on the outer exposed surface of each strand, the said butter area characterized in that it has great resistance to abrasion, the characteristics of vulcanized rubber and is generally of segmental shape in cross-section.

3. The method of applying a buffering material to the outermost strands of a multi strand. rope, which consists in first preheating a length of said rope, passing the said rope through a heated latex while rotating the rope, so as to cover the outer surfaces of said strands with a segmental ribbon of said latex, then curing the latex on said rope after said passage aforesaid.

4. A rope comprising a plurality of strands in contact with each other, in which each exposed strand carries about centrally on its exposed surface a ribbon of abrasion-resistant buflzering material, said ribbons being spaced from each other, whereby when the rope is subjected to rubbing against an object, the friction of contact is entirely taken by the butter ribbons, thus protecting thestrand material from the abrasive action.

5." The rope. of; claim 4 in which the-buficring'ma't'erial is silicone rubber. V

6. The'rope ofclaim Sin which the rubber is vulcanized and is impregnated into the material of the strands.

7.. A mutli-strand rope in which the exposed surface of each strand is covered centrally by an impregnated ribbon of. bulfering material having the characteristics of vulcanized rubber, said ribbons being helical, spaced from each other, crescent in cross-section, impregnated into their respective strands, and each with its thickest portion. intersecting a radius of the rope passing through the center of: the strand, whereby the several ribbons will. protect the strands from abrasive action.

8. The rope of claim 7 in which the curves of the crescents extend over an arc of about the radius of the outer are being the same as the radius of the strand, and only a minor cross-sectional area of each strand is impregnated and the bufiering material is vulcanized silicone rubber having about the same expansion and contraction characteristics as those of the strands of the rope.

References Cited in the file of this patent UNITED STATES PATENTS Re: 19,019 Metcalf Dec. 12,1933 166,306 Schlarbaum Aug. 3, 1875 783,574 Gray Feb. 28, 1905 2,088,822 Saladino- Aug. 3, 1937 2,125,633 Harrison Aug. 2, 1938 2,254,712 Shepherd Sept. 2, 1941 2,376,813 Robins et a1. May 22, 1945 2,591,628 Snyder Apr. 1, 1952 

